From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 3 May 2001 08:24:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 3 May 2001 08:24:11 -0400 Received: from hermine.idb.hist.no ([158.38.50.15]:49676 "HELO hermine.idb.hist.no") by vger.kernel.org with SMTP id ; Thu, 3 May 2001 08:24:02 -0400 Message-ID: <3AF14DC5.17E35108@idb.hist.no> Date: Thu, 03 May 2001 14:23:33 +0200 From: Helge Hafting X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.4.4-pre7 i686) X-Accept-Language: no, en MIME-Version: 1.0 To: Pavel Machek , linux-kernel@vger.kernel.org Subject: Re: X15 alpha release: as fast as TUX but in user space (fwd) In-Reply-To: <20010428215301.A1052@gruyere.muc.suse.de> <200104282256.f3SMuRW15999@vindaloo.ras.ucalgary.ca> <9cg7t7$gbt$1@cesium.transmeta.com> <20010430104231.C3294@bug.ucw.cz> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Pavel Machek wrote: > > > > > > Whatever happened to that hack that was discussed a year or two ago? > > > The one where (also on IA32) a magic page was set up by the kernel > > > containing code for fast system calls, and the kernel would write > > > calibation information to that magic page. The code written there > > > would use the TSC in conjunction with that calibration data. > Pavel > PS: Hmm, how do you do timewarp for just one userland appliation with > this installed? 1. Kernel solution: give that particular process a different magic page 2. User solution: Don't obtain time from the magic page. 2a By changing program source, if available 2b By switching the c library, assuming it is used Helge Hafting